The F1 teams heading back to work after the enforced summer shutdown with next week’s Belgian Grand Prix, will be relieved to learn that Pirelli has bowed to their wishes and decided against increasing the size of the rear tyres for 2014.

Just before the shutdown it emerged that Pirelli had requested some changes to the dimensions of the tyres for next year – they wanted to increase the rear-tyre width by 20mm to 400mm and the diameter to increase from 660mm to 690mm.

But today sources within Pirelli have confirmed to this website that the tyres will stay the same size.

“This was a really difficult one. On the one hand you can have sympathy for Pirelli; with new rules, no-one knows what the improvement will be in aerodynamics over the course of next season – there will be huge steps in development compared to this year for example, generating performance gains and thus significantly higher cornering loads – and Pirelli have to allow for that. They learned this lesson from the huge gains teams made with the blown diffusers, for example.

On the other hand, the last thing the teams needed now with 2014 chassis designs being finalised, was a significant last minute change like this, which would mean a lot of work in certain areas being thrown away and design teams having to start again, with very tight deadlines for producing chassis before the testing starts in January. (There is also a significant extra cost implication at a time when teams are already spending more on the new power trains)

No-one wants to see tyre failures, so Pirelli has to allow quite a margin. An increase in tyre size, as proposed by Pirelli, would have helped to produce a stronger tyre able to handle higher loads.

They don’t know what to expect because there has been no testing.

But it’s not surprising that 10 of the 11 teams were said to be against the change when it was discussed before the Hungarian Grand Prix. They feel that the footprint of the tyre should be fixed, as any change has a massive impact on aerodynamics and ride height.

The team’s headache over last minute changes

Ride Height: Currently F1 tyres have a diameter of 660mm, while it’s slightly more 670mm for wet tyres, to give more ride height to avoid aquaplaning. To change to 690mm at this stage is a real problem, as the layout of the cars will already have been done based on 660mm and to raise the cars this much is a huge difference. The rear ride height of the car is typically 100mm, so to raise it by 15mm at this stage is big.

Aerodynamic and mechanical change: The extra diameter and especially the width of the tyres will have a significant bearing on the aerodynamics of the car and the aerodynamicists would have to throw away a lot of the work they have done and start again with a different shape tyre and ride height changes. New wind tunnel tyres would have to be built with this aspect ratio of height to width, so teams can get accurate data from the wind tunnel. It will take significant time to do that with a new aspect ratio.

A change to the height of the rear wheel has an impact on pick up points of suspension, axle heights. It is very late in the day to be making that sort of change.

It is hard to explain to F1 fans just how sensitive an F1 car is to the contact patch and shape of the sidewall of the tyre, tiny differences make a big change to the numbers in the wind tunnel.

The timetable to build new cars
The issue needed to be resolved urgently as there is not a lot of time for teams to do all the new work they need to do to accommodate new tyre sizes.

The teams are up really against it in terms of getting the cars built for the earlier start of testing in 2014 (due to the introduction of complex new hybrid turbo engines, it’s been decided to allow more testing time, so the cars need to be ready in January, rather than the usual February 1 date).

Working backwards from the January tests, you need 2-3 months for chassis construction, so you really need to have the drawings released and signed off in late September.

So you can see that if teams had a load of work to redo, to incorporate these changes, there wasn’t a lot of time to do it.

It was looking especially tough for teams who buy in their power train, such as McLaren, Force India, Lotus and a possible advantage for the works teams: Mercedes, Red Bull and Ferrari.

The teams will be delighted to stay with the same aspect ratio of height to width as used currently.

I don't think power is going to be the issue as overall they may not be as powerful as this year, particularly as power is largely a function of rotation with engine speeds being restricted to a lower speed than is current, but they are supposedly producing more torque which means they will need the grip, and hence larger tyres would have been useful, but it is too late in the season for the teams.

Renault have been making their current engine just as long as the other engine builders. The last time they made any serious update to the engine they still ran their own team. Once they sold the Enstone team and carried on supplying engines to several teams RB became the leading Renault powered car. It was then natural for Renault to make RB their "works" team.

To claim the engines are optimised to RB is wrong - the V8 reached maturity some time ago. The only thing that has changed specifically for RB is the work on engine mapping via the McLaren ECU. This is all about how the engines is used not how it is built.

The 2014 power plant on the other hand will have far more RB influence - especially when it comes to the ERS so disliked by Newey.

Obviously that is what you wish for, but we will all have to wait until testing to have any idea who has married the better package with the new power units as anything right now is pure speculation. On another matter, is Redbull a works team? How does that work?

An engine supplier who doesn't have their own team will partner with one of their customers to work closely with making them the works team. This is the same as was the case with McLaren/Mercedes, and will be in 2015 with McLren/Honda.

Drawing a parallel here to the hoopla put out by Italian teams in 1952/53 regarding the power their new engines were producing. Their claims were taken to heart by Coventry Climax who ceased development of their V8 GP motor, only to discover years later that they actually lead the power stakes. In short, grain of salt's needed for the Mercedes claims.

To be fair to Mercedes, they haven't made any claims. It's all supposition and speculation by the media. The Mercedes have allowed it be known they would like a slightly larger tyre, or maybe not even as firmly stated as that, just they wouldn't object if Pirelli made one and the media swallowed the bait and the rumour mill took over 🙂

You have to hand it to them for playing the game so well - maybe the wise old owl Ross, has a few more tricks up his sleeve.

Oh, they will be able to put the power down- especially if reports that they will be generating as much as 100 bHP more than anyone else are true. I doubt their advantage would be that much, but even if it's as much as 30 bHP, that is still a big enough of an advantage to show up with the current tires. If the rear tires got bigger, they would be far ahead.

With respect I think you are mistaken. Mercedes have not asked for anything to be changed, as I understand it. I believe it was Pirelli that suggested the change and Mercedes were the only team that didn't vote against it - they reserved their vote as apparently. Because of this everyone has got it into their heads that the Mercedes engine will be more powerful than the opposition.

Well, it's an unknown. That should make anyone nervous. Or excited about the possibilities.

I have this suspicion that in the end, this change won't make much of a difference in grid order. The resources are all in the sharp end anyway. And the RBR domination has to come to an end at some point, right? May as well start accepting the reality of that possibility while the going is still good so it doesn't come as a shock the body rejects in 2014 - when it may happen. 🙂

I sincerely hope next year the engine order is the exact opposite of what the rumor mill "suggests" it will be. 2 birds, 1 stone. Je germans out the picture and might make people stop believing unsubstantiated gossip

Bigger tyres will make for faster cars, especially in the engine era when grunt will become all important. The powers that be are quite concerned about reducing speeds (beats me why), so they too would have frowned at Pirelli's suggestions too, I guess.

This has got nothing to do with gears, it's the number of rotations per second of the wheels which heats (and overheats) the tyres. This is directly proportional to the speed the car travels at. A larger rolling diameter will reduce the number of rotations and allow the tyres to cool

I agree, on the one hand the FIA are always trying to slow the cars down, for reasons of safety. But if the tyres are undersized and consequently over stressed then surely that is a safety issue as well? Damned if they do and damned if they don't, I guess.

F1 is one of the last motorsports to retain small diameter wheels. A change to 18" wheels would need a massive suspension and steering re-design. The current suspension has very limited travel and relies very heavily on side wall flexing. Take that away and the steering will be much harder and need much stronger components. Ride height will also need to be managed in a completely different way as, currently, this is often varied during a race by changing tyre pressures at pit stops.

I seem to recall reading that ferrari's move to pull rod suspension last year (and, presumably, McLaren this year) was largely to do with trying to introduce and manage chassis twist to keep 4 wheels on the ground. This would be similar to motorbikes recent understanding of frame flexing as a significant element of "suspension" movement when cornering.

I don't think it was anything to do with slowing the cars down. Pirelli and Michelin went head to head for the '11-'13 tyre supply deal and Michelin wanted the 18" wheels so they could use their low profile LMP tyres just customised to suit F1.

Considering the majority of the teams didn't want these changes to the 2014 tyres, I think this is the right decision by Pirelli.

First off, the teams have their own engineers so if they believed a change in the tyres would have made that much of a difference then they would have agreed to the changes.

But seeing as they have declined, it just shows, Pirelli were just trying to go ultra conservative for no apparent reason like they have shown with their tyre choices in the past.

Now, I hope the people at Pirelli haven't been playing solitaire during working hours because not only have their 2013 tyres been a headache but also they should have requested for these 2014 changes a long time ago, matter of fact, during winter testing but not now.

Anyway, from the looks of it, 2014 is shaping up to be epic for it's all everyone thinks about.

I'm willing to bet that 2014 is actually a blowout, with one team getting the new rules right over all others, and it being a "let's watch the number 2, 3 and 4 teams battle it out" kind of season... Hard to know if it's Mercedes or RB that's going to hit it big next year. McLaren without Dennis just isn't going to be formidable anymore, and Ferrari, they're not exactly hybrid engine experts and I see them dealing with the transition rather poorly (Those road Ferraris may look nice and go fast, but they are not really tech marvels like the auto companies trying to compete on value and solve 21st century struggles, rather than vanity pieces...).

Thanks for your answer, and thanks for all the work you put in to maintain and provide this excellent website for us fans.

I think it is safe to say that this is the only website where fans have such a direct connection to the sport, where we can have technical and other questions answered by someone with real insights into the sport. Also, I really enjoy the civilized discussions on here.

I am off on holiday to Italy today, where I won't be able to watch Spa live on TV next Sunday. Sadly F1 is no longer live on free-to-air channel RAI1. Is it only Germany left now with all races live on free-to-air?

Agreed, very annoying. I appreciate the need to advertise but why can't they do a split screen and at least keep the video feed running in the background, you can even have the BBC web radio commentary on and mute the advert audio.

The problem with delaying the race is that none of the web based live race stats would be in sinc.

While the entire F1 season is on FTA in Australia, the coverage is pretty shocking as they break for looooong add breaks at the most inopportune time. There could be a wheel to wheel battle for P1 and oh of to an add break, AGAIN. Its really very frustrating.

I appreciate Channel 10 needs to show adds for revenue - why not show the race on delay i.e. start it live, an add break on say lap 10, then resume the coverage on lap 10. This way fans don't miss out on any racing and Channel 10 get their revenue.

Totally off topic this but my mates were going on and on about at the match earlier. Would love some inside intel on it to shut them up! What does it mean for the British GP and who are the new bosses? Looks really important if this is true:

The British Racing Drivers Club, the owner of the Silverstone circuit, is expected to announce next month that the British Grand Prix venue has finally been sold on a long lease to a real estate developer.

The 800 BRDC members oppose an outright sale but the club has been trying to sell a lease on Silverstone for several years. That process was accelerated in December 2009, when it secured an unprecedented, 17-year contract with Bernie Ecclestone’s Formula One group. Facility development was a condition of the deal and in 2011 the BRDC invested heavily in changes to the track configuration and construction of a new pits and paddock complex. The works contributed to the BRDC’s debt pile of more than $40 million.

James my understanding of this was that the BRDC sold the circuit but still own the rights to the lease - meaning they can still operate the British GP. The sale of the land will allow the development of a business park and other assets at the circuit whilst the circuit still remains tied to the British GP via the lease and the rights.

It says the lease is 150 years which is no different to owning something. Most houses in places like London have leases for 150 years or more and the people who buy them are the owners. Dont see why Silverstone is any different but what will the new lot do?

Of course the geometry and general engineering is well understood. However with F1 being so extreme and the current components having been optimised for aero, current geometry and minimal weight the change is massive. Some current components break - changing to bigger wheels would make the shock loadings far greater and the learning curve for brake cooling and heat management would be pretty steep. The suspension would have to be far stronger and heavier leading to more space being needed in the front of the monocoque - and, therefore, significant changes to the whole car aero concept. If, as you suggest, it increased front downforce then, again, this effect the whole car as McLaren have suffered this year. Many have suggested that their problem is a poor front wing - but they are running a lesser front wing because they have not caught up with the rest of the car. Front - back aero balance is extremely important.

Bigger wheels=bigger brakes=more mass for the head to spread on=less heat.

As for the strength of the suspension, once again: MOST other formulas have low-profile tyres. F1 is the one that's grossly out of date. There are plenty of racing engineers out there that know how to solve these problems. Yes, this would have probably been an unnecessary distraction had it been set to appear in 2014, but I really don't see why it can't be pencilled in for '15.

Beyond all that, in the current F1 cars ANYTHING that takes focus away from aero surely must be a plus... so the potential for such a change to increase downforce, is the one thing I fear could make the idea backfire.

James it's another perfect example of the FI really not taking a lead role and thinking things through. As much as I dislike Pirellis take on things there is a real lack of consideration going into the rules. The powertrain formula has been in discussion for what 2 years now. Since Easter Pirelli have been pleading for more testing and feedback for 2014 ( hence Merc trial) and now here we are another season almost gone and we have heavier cars and more torque with the same basic tyre!- aside of the reliability concerns is its a sporting and entertainment concern we will not see the full performance of the new cars because they are again limited by that demonised word- tyres!!.

Of course the teams don't want to start again - the real question is why have the FIA sat on their hands without factoring this in early in the year ot even last year and have a more open dialogue with the teams and tyre supplier - especially when we have a Paul Hembrey beating his head on the wall for months suggesting they do it! Really really Ridiculous!..last thing anyone wanted to be talking about in 2014 racing season.

It is all about efficiency, both aero and energy. It is not about peak numbers so i do not buy much into mercedes Horse power advantage much.Plus the price difference on mercedes and renault is to much for no reason at all.

It's not about power, it's torque. The electric motors will have no problem spinning-up the rears... so increasing the tyre's footprint would make quite a bit of sense.

Of course what would make even more sense, would be a move to the lower-profile tyres, as used in... erm, let's see: oh yeah, everywhere except F1. First Michelin, then Avon then (drum-roll please) Pirelli advocated this change, back in 2010, i.e. when Bridgestone was leaving the sport, but it was quietly forgotten afterwards...

I thought it was generally accepted that the 2014 power units are being found to deliver more power than had been expected at the beginning of the year. How could Pirelli have been expected to anticipate the power output would be 10-15% more than all the leading engineers were telling them would be possible.

With this being learnt so near to the the first race with the new power plants it is not just the tyres that will need to be considered. January testing will really test the teams ability to think fast!

I would assume the the one team that was in favor of changes is Mercedes, correct? Apparently they have an engine that can be as much as 100 HP more powerful and yes, they would need to have different tyres:-)

The engine regulations being what they are, I don't believe they will be more than a 20 HP difference between the strongest and weakest. And much of that difference will be due to drivability considerations i.e. some manufacturers will sacrifice a few HP at peak revs in order to get a broader power curve.

The interesting question will be, who is going to have the most reliable motor next year? There's a good chance that one of the three will be plagued with reliability issues for at least the first half of the season.

It's my bet that Pirelli will go really conservative with compounds and construction in 2014 because they are to some extent going into the unknown. the sensible thing would have benn larger rear tyres, but I guess we will have to wait until 2015 for that.

If I'm honest I would rather see the return of the fat front tyres from 2009. They looked ridiculous, but with such a forward bias of grip they oversteered like there was no tomorrow.

As someone who watches a lot of on-board footage, I miss that (and the characteristic 'DRS wobble' that left with the banning of free DRS usage for this season too... though this isn't really related).

Great idea. Why are we asking the teams what they want? Because the answer will be cars on rails, no surprises. When what the fans want is cars scrabbling for grip under braking and oversteer exiting the corners.

And while we're on it, can we please have the wide lens on-board camera removed and replace with a "normal" lens? It's alot more fun to watch the old onboard cameras where we can actually see how close the cars are than this stupid wide lens footage which makes the cars infront disappear into distance.

So the good-old idea of moving to more 'normal' tyres, i.e. away from the outdated and patently ridiculous high-profile 'balloon' tyres of today, is probably dead.

At first I thought it might be introduced later, as a deference to the already plentiful changes for 2014. But if the teams need to agree, even for a change as basic as the one proposed by Pirelli (to compensate for the 2014 engine's ability to spin the tyres, I assume), I suppose a change as big as moving to low-profile tyres (AND suspension with radically increased travel, to compensate) is out of the question.

My understanding is that the teams did not agree because they have already proceeded with the design of next year's car. In the present financial climate, where a few teams are on the verge of collapse, most could not afford to redesign the car in order to incorporate the new tyres. My hope is that the subject is put on the table for discussion for the 2015 season.

This is ridiculous and unfair on the part of the teams. They whine now and force Pirelli to comply with their wishes saying they do not have time to make changes. But the only reason they would not have time is because the teams- and F1- wasted time bickering over tire regs. Pirelli said several months ago they needed the teams to come to an agreement and needed F1 to finalize their contract so they could provide the teams with the 2014 tire specs in good time. Everyone needs to remember this if and when the high torque engines over-power the narrow rear tires in 2014 and we all complain that the drivers are driving at 70%.

It's true. A cynical person would see politics from the teams making sure that there is always a high profile supplier where they can place the blame for their own failures.

This didn't work very well with the fans blaming alternator suppliers but when Vettel blames the tires for costing him the win, when all other drivers are on the same tires, it seems to work. When DiResta or Button blame the tires for costing them time in qualifying when all other drivers, and their teammates, are on the same tires it works.

Yeah F1 has been talking about it for years but as usual done nothing.

There is way to much politics and far less relevance being looked at.

There is a dinosaur running F1 with Stone Age mentality. The automotive industry had energy recover systems years ago and now only in 2014 F1 are doing it- under much protest of that same dinosaur! And now that we have it, F1 is still run on rims minis run on. The FIA needs to collaborate with the tyre supplier and the teams to make it happen.

I suspect the commercial agreement with Pirelli is something te FIA never really wanted and Bernie won on the money side of things again!

I wondered how low profile tyres might look on F1 cars. Not bad it seems - if the Le Mans racers are a guide.

I'm sure F1 will come up with some fancy aerodynamic tweaks and tricks. Shame that the opportunity is missed. But its not Pirelli's fault - they've been asking for contractual and rule clarity quite early on.